Tolerance Specification and Analysis

Abstract By employing Taguchi’s concept to mechanism synthesis, this paper presents the theory and technique to identify a robust design, which is the least sensitive to the tolerances, for mechanisms and to determine the tolerance specification for the best performance and manufacturability. The method is demonstrated in finite and infinitesimal position synthesis. The sensitivity Jacobian is first introduced to relate the performance tolerances and the dimensional tolerances. The Rayleigh quotient of the sensitivity Jacobian, which is equivalent to Taguchi’s signal to noise ratio, is then used to define the performance quality and a sensitivity index is introduced to measure the sensitivity of the performance quality to the dimensional tolerances for the whole system. The ideal tolerance specification is obtained in closed form. It shows how the tolerance specification affects the performance quality and that the performance quality can be significantly improved by tightening a key tolerance while loosening the others. The theory is general and the technique is readily adaptable to almost any form and type of mechanical system, including multiple-loop linkages and mechanical assemblies or even structures.

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Tolerance Specification and Related Issues for Additively Manufactured Products

Volume 1A: 35th Computers and Information in Engineering Conference ◽

10.1115/detc2015-47531 ◽

2015 ◽

Cited By ~ 3

Author(s):

Gaurav Ameta ◽

Paul Witherell ◽

Shawn Moylan ◽

Robert Lipman

Keyword(s):

Free Form ◽

Complex Geometries ◽

Geometric Accuracy ◽

Current State ◽

Manufactured Products ◽

Internal Cavities ◽

Tolerance Specification ◽

Functional Features ◽

Traditional Manufacturing ◽

Am Processes

Additive manufacturing (AM) has gained increased attention in the last decade as a versatile manufacturing process for customized products. AM processes can create complex free-form shapes, introducing features such as internal cavities and lattices. These complex geometries are either not feasible or very costly with traditional manufacturing processes. This creates new challenges in maintaining and communicating dimensional and geometric accuracy of parts produced. In order to manufacture a product that meets functional needs, the specification of those needs through geometry, material and tolerances is necessary. This paper surveys the current state and needs of geometry related accuracy specification mechanisms for AM, including a review of specification standards such as ASME Y14.5 and ISO 1101. Emerging AM-related tolerancing challenges are identified, and a potential plan of action is put forth for addressing those challenges. Various issues highlighted in this paper are classified as (a) AM-driven specification issues and (b) specification issues highlighted by the versatility of AM processes. AM-driven specification issues include build direction, layer thickness, support structure related specification, and scan/track direction. Specification issues highlighted by the versatility of AM processes include, region-based tolerances for complex freeform surfaces, tolerancing internal functional features, tolerancing lattice and infills. Basic methods of solving these specification issues are also highlighted.

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Application of TTRS Method in Industrial Practice Tolerance specification for Industrial Cooling Water Pumps

Global Consistency of Tolerances ◽

10.1007/978-94-017-1705-2_26 ◽

1999 ◽

pp. 251-260 ◽

Cited By ~ 1

Author(s):

O. W. Salomons ◽

R. E. Begelinger ◽

E. Post ◽

F. J. A. M. van Houten

Keyword(s):

Cooling Water ◽

Industrial Practice ◽

Tolerance Specification ◽

Water Pumps

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A Dynamic Implementation of Keller’s Sketching Rules for Burmester Curves an Approach to Sensitivity Analysis

22nd Biennial Mechanisms Conference: Mechanism Design and Synthesis ◽

10.1115/detc1992-0329 ◽

1992 ◽

Author(s):

J. Keith Nisbett ◽

Sanjay K. Gupta

Keyword(s):

Sensitivity Analysis ◽

Geometric Approach ◽

Automatic Generation ◽

Linkage Design ◽

Tolerance Specification

Abstract Keller’s sketching rules for Burmester curves are implemented on the computer for automatic generation of valid and invalid regions for the existence of the curves. The rules are based on the poles of the coupler motion, which in turn are directly related to the precision positions. All six possible unique arrangements of poles are used in the sketching rules. The sketching rules provide a useful heuristic and geometric approach to relating the sensitivity of the curves to small changes in the pole locations. The regions and the curves are dynamically updated as the poles of the specified motion are moved by the user. The new curve obtained is checked to verify satisfaction of original tolerance specification on the precision positions. The procedure shows promise for artificially intelligent approaches to linkage design.

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Implementation of Parameterized Work Piece Deviations and Measurement Uncertainties into Performant Meta-models for an Improved Tolerance Specification

Proceedings of the Design Society: International Conference on Engineering Design ◽

10.1017/dsi.2019.357 ◽

2019 ◽

Vol 1 (1) ◽

pp. 3501-3510

Author(s):

Andreas Michael Müller ◽

Thomas Oberleiter ◽

Kai Willner ◽

Tino Hausotte

Keyword(s):

Production Costs ◽

Work Piece ◽

Geometric Tolerances ◽

Tolerance Specification ◽

Close Cooperation ◽

And Function ◽

Product Description ◽

Tolerance Management ◽

Technological Products

AbstractGeometrical work piece deviations are unavoidable and directly affect the function and quality of technological products. Tolerance management is regarded as a crucial subtask of the development of technological products, because it ensures the function as well as a sufficient product quality while maintaining reasonable production costs. That means, that geometric tolerances as an essential part of the product description greatly affect the functional capability, manufacturability, mountability, verifiability and the costs of the final product. The research group FOR 2271 was founded to enable the computer-aided specification of tolerances, which meet the requirements of production, assembly, verification and function by close cooperation between the departments responsible for product design, assembly and metrology. The aim of this contribution is to determine the manufacturing process scatter as well as the measurement uncertainty and establish ways and means to include that information into efficient meta-models, ultimately enabling improved and accurate tolerance analyses.

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